80 Thermal Pastes Tested

Prior to our 33-Way Thermal Compound Comparison article published back in March 2008, there had not been another project of its size available online. So when Benchmark Reviews revealed our test results, it was a surprise to find that many overclockers had been ill-informed by marketing hype and misleading enthusiast opinions. Benchmark Reviews later published several other complimentary articles for performance hardware enthusiasts, offering an instructional guide on Thermal Paste Application Methods and testing for the Best CPU Cooler Performance. As the author to both of those articles, I have discovered that the most critical factors pertaining to thermal cooling performance seems to be overlooked. In this massive follow-up article, which was built from entirely new project data taking over one year of research to publish, our collection of test material has grown to include every product we could acquire from the marketplace. Benchmark Reviews has received advice of industry experts, manufacturers, and elite overclockers to bring you this comprehensive 80-Way Thermal Interface Material cooling performance comparison benchmark test.

Because testing has been conducted over a 16-month period, this project has suffered numerous delays. At one point this project was completely restarted because the test system motherboard failed, which rendered months of progress wasted because temperature readings are specific to onboard thermistor diodes and BIOS calibration. Other delays came from waiting on manufacturers to supply test samples. While most of the thermal material used in our tests was purchased from online retailers in the USA, several samples were supplied directly from the manufacturer (due to lack of North American retail availability or recently announced product launch). Our results are certainly worth waiting for, yet the true focus of this article isn't meant to publish a chart with numbers, but instead it's meant to grade product performance and identify the non-performers. More than any other factor, and vastly more important than any one thermal paste, the surface condition and mounting pressure have the greatest impact on cooling performance. Unfortunately this is a conundrum for our 80-way Thermal Interface Material article, because our grades for thermal paste materials will be read by visitors who already have improved mounting and surface finishes... making a particular product's performance moot.

Thermal Conductance is the transfer of energy from a source to a receptor. In relation to computer hardware, this energy is heat and the thermal transfer happens in key locations such as the processor and motherboard chipset controllers. In the most ideal environment, this heat transfer would happen without resistance or reduced efficiency. For example, under perfect conditions a processor would transfer every watt of thermal energy directly to the cooler. However it is because our performance computer hardware products are often made from dissimilar metals that we must rely on an interface medium to connect the source and receptor with as little resistance as possible. A key factor in selecting a thermal interface material is the relationship between bond line thickness (BLT) and thermal resistance.

The importance of using a quality Thermal Interface Material is critical for improving thermal conductance between components having imperfect contact surfaces and/or inadequate mounting pressure. Even now as processors are built to strict tolerances and consume less power, overclocking still demands the highest order of performance from the system's cooling equipment. As a byproduct of overclocking the processor, certain motherboard components such as the northbridge chipset must also mate together perfectly with the heatsink cooler to keep system bus speeds operating at a stable level. Thermal output from processors has steadily improved, while GPU heat output is steadily rising. Video cards are now the hottest item on the market, literally, and must be cooled with high-performance solutions to ensure the best video game graphics experience possible. Everything that creates heat relies on the cooler, but the cooler itself relies on the interface material to make a connection with very little thermal resistance.

Benchmark Reviews has seen a lot of products made for the purpose of delivering better performance. Some of these products exist for overclockers and enthusiasts, and often times help enthusiasts coax performance out of otherwise tame hardware. Other cooling products sometimes only deliver the empty marketing claim of wishful improvements. Of all the products we have seen and tested, one particular category always stands out as the culprit for over-hyped promises: Thermal Interface Material (TIM). Of all the heatsink compounds and thermal pastes made and promoted, they must all only concentrate themselves to deliver the simple function of mating the CPU to the cooler with the highest thermal conductivity possible. Of course, some work better than others, and this is exactly what Benchmark Reviews intends to discover and reveal. Please join us for the comprehensive testing of 80 different Thermal Interface Material products.

This comparison review article has three major objectives:

Educate enthusiasts on the importance of contact surface preparation and proper mounting pressure

Inform overclockers on the best methods for applying thermal paste

Grade the various thermal pastes in their ability to transfer heat energy

We hope you will appreciate the labors taken to produce this report, and the tireless research testing conducted by Benchmark Reviews for the sole purpose of allowing you to achieve the best overclock performance possible from your computer system. This article may be about thermal paste, but the underlying message is how meaningless TIM is when you're doing everything else correctly.

Makes me want to know more detail about how to prepare/polish the heatsink surface as it seems really important. Like exactly how you go about it and exactly what materials are used? I imagine you could make it worse rather than better by not doing it well?

Got here off a random review posted on a thermal paste product page but this is really very timely info. I'm starting my second build tomorrow, and my only challenge last year was the paste process. This article is so good I might pop open my existing PC and reapply better.

Haven't even seen the result charts yet, but just having the pictures of different ways to apply the paste is hugely helpful. Thanks again!

tuniq tx-3 is a waste of money the A/S ceramic is just as good if not better im running a i7930 and iv tested both and the A/S beats it by almost a full degree ! and cheapers and you get WAY WAY MORE !!! 22grams almost 8cc worth ,so if you want to throw your money away buy tuniq

Good to know that the syringe of AS-5 I've had in my desk for 5 years was worth the $15 I paid for it. I've used it in several low-end (P4, not Xeon) custom-built servers that run 24/7 and never had a heat problem with them. The thin-coating does seem to do the trick.

Great article. Thanks for all the work.

If you're looking for a follow-up article - investigate why the machine OEMs use such a thick layer of ITM in their boxes when it's blazingly obvious that a thin layer works much better.

How flat is the pressed metal surface of a processor say an Intel I7-###. Is there an engineer out there who has checked this out and was the inspection carried out at room temp or at say 50 deg c.?. Now thats a question.

I've checked the flatness of a couple of C2D/Q IHS's and they tend to have a dip in the middle. I used to lap them to get them flat but it's long and tedious work and, as the best lap is a wet lap, fairly dangerous to your CPU as it can be wet for a long time.Now I just use a bit more TIM. I didn't mind lapping my old E4500 as there wasn't much at stake but I didn't lap my (current) O/Ced QX9560.

I've checked the flatness of a couple of C2D/Q IHS's and they tend to have a dip in the middle. I used to lap them to get them flat but it's long and tedious work and, as the best lap is a wet lap, fairly dangerous to your CPU as it can be wet for a long time.Now I just use a bit more TIM. I didn't mind lapping my old E4500 as there wasn't much at stake but I didn't lap my (current) O/Ced QX9650.

I notice that there are a few silicone products that made the cut. I find that Radio Shack brand silicone grease gives me lower temperatures as compared to any metallic product I've ever tried. I don't know who actually makes it, but I'll be using it on my new i7 system when I fire it up next week. I tried their silver product too, which didn't work as well. Test it against these A-rated products one day.

About 8 years ago someone did a review [Cannot remember who] on the 10 or so TIMS that were available to the computer enthusiast at that time. I believe Arctic Silver 3 was top dog followed by 1 incarnation of Shin-etsu. Number 3 was Radio Shack white thermal silicone based Tim that cost $2.25 back then. I happened to run out of Arctic Silver one night while assembling a build for a customer and I had a small tube of Radio Shacks white Tim. I used it on a a few builds and was surprised at the performance. The only thing that was worth mentioning stating is that it does dry out after 3-4 years and needs to be replaced IMHO.Anyway, great review, later........................................

You mention the best materials are carbon based. When I scan all the results, I didn't see a single product based on carbon. Did I miss it? You said all the best are now using carbon. Where are the results of carbon based TIM? I would go for them based on what you've stated. Please help. Thanks.

Wow, this test article was amazing. I tip my hats to all involved for creating such an in-depth and comprehensive test on thermal pastes. It was a pleasure to read through the full article, I especially liked analysis into the different ways of applying the paste, I've always spread the paste out with a razor and never gave much thought to other methods. I especially liked the idea of spreading the substance out with a slick plastic surface.

There is a slew of information in this article and it's definitely going into my bookmarks. Great job and many thanks for the extensive effort that was put into this project!

Rahul: DonÂ´t call JG "dumb". The author quite correctly sums up by saying: "perfectly flat metal on metal with no material in-between is your ultimate goal". TIM is after all a not too good heat transfer media as compared to metal and becomes increasingly necessary only when that goal is not achieved and to the degree that it is not. It is perfectly possible that in some cases routinely applying TIM actually degrades performance of the cooler. Maybe the measure of TIM effectiveness perhaps should start with a no TIM test. I would like to see that, too.

If you're gonna do a "1 layer spread" would it not be better to spread it on the CPU heat spreader than that of the air cooler? Reason being, the CPU heat spreader has a smaller surface area. Seems obvious.

I found your article while doing cross comparisons and testing for the best thermal compounds and must say I was very impressed! Its awesome to see someone who finally put the quality, effort and time into writing a real review of the above products, techniques and other aspects in regard to the thermal compounds. I especially found the densities and composition charts most informative. I spent several hours looking for something that would give me such information and it was quite irritating not finding a simple comprehensive source until I ran across your article. So I just wanted to stop by and tell you what an awesome job you did with your article and commend you for a very thorough, insightful, and highly informative review process. If I should create a really awesome comprehensive review company you'll be one of the people I'm going to have to track down for a full time job to review things. Excellent job man.

One of THE BEST articles/reviews I've ever had the pleasure of reading. Not only because of the reviewer's persistence and professional attitude throughout the entire reviewing process (which at least at times I'm sure must have been both boring and tiresome!), but I'm especially satisfied to see that even though the end-point outcome of the whole review turned out to be of some marginal importance on a system used by the average Joe out there, nevertheless that was clearly pointed out from the beginning and throughout the whole article, instead emphasizing the importance of understanding, preparing and finally applying the METHOD of TIM used rather than what to use! Still giving excellent comparison between different brands using a stable and consistent testing method and nonetheless also giving final recommendations. Thank you very much for your immense effort and please keep up the good work in the future :)

Great methodology within defined limitations. Acknowledgement of the effects of technique. Superbly honest. A commitment to testing products over time. I really am gobsmacked by the quality of this review. Any lab I know would by glad to have you onboard. Thanks for a well thought out review Olin.

Amusing that GC Electronics 10-8108 runs right up there with AS5 and is even better than AS Ceramique. 10-8108 costs about $2.50 for a 6.5 g tube vs $5+ for a 2 g tube of Ceramique. From personal experience, I concur with the results that 10-8108 is better than Ceramique.

Superb job of testing, definitely the most comprehensive guide I've seen. It looks like it could stand to be updated; as I know that some of the products -- most notably IC Diamond -- have undergone changes in their formulation and properties, so the tests in this article no longer apply. Other than that, it's definitely my go-to place to refer anyone looking for TIM info.

Epic article. Can't but echo all the praise dished out in the previous comments. Must say though, that adding the viscosities of each thermal goop was a brilliant move as it's hard to find any real info on them elsewhere.

I read front start to finish and really appreciate the points you made about contact surfaces and allowed curing time. Paste aside, there are some solid gains to be had from the rest of the article. Thanks for your hard work. Prepping for bf3!

This is an excellent, comprehensive article comparing various TIMs. I have relied on it and send people to read it all the time. However, it is 2.5 years old now and many people just come her and look at the date before shrugging and saying "meh, it's two years old, there are newer TIMs on the market now".

I would love to see some of the newer TIMs tested and added in a section at the end of this article as an addendum. I have been very interested in the metal TIMs I have seen around. Some people claim they are getting a 10c difference using a metal TIM over a TIM like AS5. I've never tried a metal TIM myself, and although I hear they are a little bit of a pain to clean off I would still like to try one.

As it stands this is still the best article around on TIMs, but it could use a little bit of an update.

My conclusion clearly states my future intentions. It doesn't matter how many new TIMs come to market, if you properly prepare the surfaces and ensure great mounting/clamping force, they'll all perform nearly the same.

As I mentioned in my comment, some people are claiming that they have reduced their temps 10c by replacing their TIM with newer metal TIMs (like liquid ultra).

Saying they nearly all perform the same may have been true 2-3 years ago, but not so much now. I would sure like to put some of those claims to the test, but since I can't get TIMs like Liquid Ultra locally I can't test them myself.

Frankly, until they are, no one can make any claims regarding them and be taken seriously, and that includes the naysayers. I have seen these claims on ocn. I can't counter them because I haven't tested these new TIMs.

Only if you care about the temps in your system. Lots of people just have whatever their system came with, and I'm sure as long as it works they don't care.

Then there are the people this article is aimed at, the enthusiasts who care that the difference between the poorer TIMs are better TIMs can be 5c. When you're overclocking, and aiming for a particular clock rate, then 5c can be pretty important.

Your question is akin to comparing the fuel in a street car to that in a race car where a few octane can make a difference.

I read with great interest ALL of the article, and found it to be solid, Fair, and a FULL PICTURE of the subject matter.

AND when I read all of the comments that were written thanking you and praising you for your all of your hard well thought out work, Nice elements table too, Then there were the "when are you going to do a new one" Persons. I have to just shake my head sometimes in wonder at the different densitieses that are exhibiteded in such exchanges.

I have worked in metallurgicaliFieldeild much of my life and pretty well versed in such matters, had to laugh at the suggestion of soldering the processor to the cooler, I wonder do people actually take the chance on refinishing the surface of the processor? I can see flat lapping the cooler but I would never touch the processor, except to install.

Thank you for all of you efforts and I enjoyed all of it and agree with all of your findings.

This definitely solidifies my point on the fact that AS-5 is still one of the best (tied for first). Many people that test it do not do the 200 hours of curing, and if they do, its not the proper way with the heat cycles.

This article will be true for a very long time, It really shows how the mb and cooler retailers fail the public w/the likes of pushpins and shotty pitted cooler surfaces. As shown the most expensive is not always the best. I run amd x3 445 4core opened on a asrock w/cm212evo antec tim my temps x3 19/20c x4 26c loaded p95 x4 32c. for a $22.00 cooler it works as good as the best of them.I would like to mention graphics cards also need the right paste, I changed mine now runs 6c lower that is alot of cooling. To benchmark I always check with your reviews before buying anything I know that it's going to be done by skilled personell looking for the truth and not what some retailer is trying to put over on the novice. thanks for the hard work it really is appreciated.

This is the kind of article that makes the open web worth going to. Was super helpful and I can attest to the fact that (consistent with the ratings) IC7 beat the pants off AS5. After 2 applications of AS5, I have a 55w processor running significantly cooler than I ever got a 45w processor to run with 7 applications of AS5.

I for one cannot say enough about thermal paste, I presently am using antec6 on my cpu and gpu and the temps have gone down significantly in idle and under stress, if your system cpu is running above the 20's at idle, you need to check your paste. Oh and I have one of the cheapest after market cooler, the cm-212 evo my normal idle is 18c to 21c. I am not affiliated with any corporation this is strictly my own experience.P.S I also put the antec 6 on my 5670 card voided the warrantee, but I more than likely extended its life its getting 32c vs 40c plus before.

I have been looking for a comparison of TIMs for over 2 years. I have found many but there was a noticeable assumed problem with all of them. When comparative results are limited to only a dozen or so products it leaves me wondering if any given test could be skewed toward one product or another.

When you put up 80 products agains each other the possibility of favoritism practically vanishes and the real picture begins to emerge.

I do agree with several here who have expressed wishes this test included results after long term use and curing of the TIM application(s). At the same time I must understand the time and cost required to do such an in depth test with so many products. All in all considered this is a great trade off.

I just had to say thanks. AS5 really works. Brought my e7-8860s X(4) down to 36c after hours or running algos. Was 50C Now 36F non load. With heavy 80 cores load at high priority in task mgr can't get close to shutting down like i used to. BSOD but not blue screen it would turn off with RadioCrap thermal paste. Max temp 50c thats it was ... so hot it shut down. All financial Pros use this.

Thanks, Olin, for a well-designed and -executed study. (I have to admit, I'm curious how you managed to maintain +/- 0.5C !)

One thing I think could have really driven your important point home would have been to add a short table at the end, showing the "Before and After lapping" temp results using an A+ and a D- (perhaps thin and thick examples of each) on the illustrated Ultra-120 eXtreme heat sink, thus demonstrating the benefit obtained from prep, and the much lower importance of the paste used.

Also, as someone who laps metal pieces flat and polishes them to a mirror finish in my daily work, checking with an optical flat/monochromatic light, I'd like to emphasize to the masses that a FLAT surface is not the same as a SHINY one. Obviously, flat AND shiny is what we're after, but it's important not to "unflat" a surface in the pursuit of "ultrashiny", which is easy to do if not performed properly.

Finally, in answer to a question asked upstream to the effect of, "why would anyone not overclocking worry about this stuff?"-- those of us who are in quiet environments, particularly audio, like to keep our stock-volted machines as quiet as possible, which is partially accomplished by improving heat dissipation thus enabling lower, quieter, fan speeds.

Thanks again for the insane number of hours this (and previous articles) must have taken, including the excellent presentation.

I appreciate your feedback! It would have been great to have someone like you to assist with achieving the ultimate flat surface for these tests, setting the bar even higher for anyone with ambitions of creating a future article. Unfortunately, this product was beyond arduous and required so much time and attention that I will never attempt it again. Hopefully most the products and data are still relevant, because it's one of a kind.

Your article on thermal compounds is the clearest written and best researched work on the subject that I have come across. I'm appreciative of all the effort, and patience, that must have gone in to such a complex project. Many thanks, Mr. Coles!

Outstanding, meticulously done, Test Review!! I know this test was done in 2009, but the every one of the scientific principles and procedures based on those principles are still applicable. I think a more commonly indoor/ambient temperature would have been 24C/75F instead of the selected 20C. But then, the increased ambient temperature difference is proportional and can be calculated easy enough so please don?t take that as some ?big deal? on my part.

However, I do feel I must point out that acquiring perfectly flat, high-polished, metallic surfaces is not ?impossible?. As a first-class machinist, (job-shop and proto-type spe#t), as well as a mechanical engineer, for over 23 years, I can recall machining a number of special valve related devices for the aerospace industry, (to name just one), that I then hand lapped to a #2 to #6 micro-finish on a number of jobs.

In one company I worked for, (supervisor capacity in a production company), we had a lapping machine used to lap high-pressured oilfield compressor valve rings, (nonmagnetic).

Some of the additional tests we would run on these rings, (aside from micrometers and indicators), was to slide a number of rings together after the lapping process. We would then fill the resulting ?cylinder? stack with rubbing alcohol and make sure it didn?t seep through, (which of course, it didn?t).

They were so flat that it was impossible to pull the rings apart without sliding them off. BUT I AGREE that the process would raise the price of the cooler so high as to make it ?unsellable? and therefore impractical to the manufacturers and hence, may as well be ?impossible? to find.

But I?m just mentioning that as a FWIW-FYI kind of thing and it has no practical relevance to the EXCELLENT review and all the procedures there in.